\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx,ninecolors}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\begin{document}
\small
\begin{tikzpicture}[>=latex,scale=1.0]
  \foreach \x in {-2,-1,...,2}
  {
    \draw[<-,densely dashed](-3,\x)node[left=3mm]{$-$}--(3,\x)node[right=3mm]{$+$};  
  }
  \draw[ultra thick](-3.15,-2.5)--(-3.15,2.5)(3.15,-2.5)--(3.15,2.5);
  \draw[fill=cyan!30!lightgray](-0.15,-2.7)--++(-0.85,0)--++(0,-1.5)--++(2,0)--++(0,1.5)--++(-0.85,0)--++(0,-0.8)--++(-0.3,0)--cycle;
  \fill(-0.15,-3.5)--++(0.12,0.15)--++(0.06,0)--++(0.12,-0.15)--cycle;
  \draw[gray,->](0,-3.35)--(0,1.6)node[above,text=black]{$\gamma$};
  \draw[gray,->](0,-3.35)..controls(0,-2.5)and(-0.1,-1.2)..(-0.3,1.0);
  \draw[gray,->](0,-3.35)..controls(0,-2.5)and(0.1,-1.2)..(0.3,1.0);
  \draw[red!50!gray,->](0,-3.35)..controls(0,-2.7)and(-0.3,-0.8)..(-1.3,0.4);
  \draw[red!50!gray,->](0,-3.35)..controls(0,-2.7)and(-0.3,-1.2)..(-1.3,0.0)node [left,text=black]{$\alpha$};
  \draw[red!50!gray,->](0,-3.35)..controls(0,-2.7)and(-0.3,-1.6)..(-1.3,-0.4);
  \draw[blue!50!gray,->](0,-3.35)..controls(0,-2.4)and(0.5,-0.8)..(1.6,-0.5);
  \draw[blue!50!gray,->](0,-3.35)..controls(0,-2.4)and(0.5,-1.4)..(1.6,-1)node [right,text=black]{$\beta$};
  \draw[blue!50!gray,->](0,-3.35)..controls(0,-2.4)and(0.5,-2.0)..(1.6,-1.5);
  \draw[thin](-0.6,-3.7)--++(160:0.7)node[left]{铅};
  \draw[thin](0.1,-3.45)--++(-10:1.5)node[right]{放射性样品};
\end{tikzpicture}
\end{document}